Sharing external USB drive

[kool1zero]

okay, so i have a 1TB external hard drive and i wanna share it between my

W7 ult desktop(the one its connected to,wired to router),
another desktop (xp pro,wired connection as well),
a w7 ult laptop (wirelessly),
and a xp pro laptop (again wireless)

the complicated part is i wanna password protect at least part of it from the rest of my family so i can hide my ....stuff....

 

[kool1zero]

anyone? i've been doing some reading and it seems like if i want to share this drive from this computer and password protect it, then im going to need to switch from a workgroup to a domain, which i am not opposed to doing, but would prefer to avoid. i have from my reading gathered it would be a complicated process and i dont quite understand domains all the way yet....

SO! if anyone has a simpler idea than switching from workgroup to domain in my household and setting up a tree structure please offer them!